The Role of Human Gut Microbiota in HIV-1 Rectal Acquisition, Replication, and Pathogenesis

 描述(申请人提供)：肠道是HIV感染的重要部位。在美国，大多数新的艾滋病毒感染是通过直肠获得的，而艾滋病毒的直肠传播是全球艾滋病毒感染的一种重要方式。肠道也是VIRS复制、CD4+T细胞耗尽、炎症和微生物移位的重要部位。共生肠道微生物群保护肠道免受病原体的感染，然而，肠道微生物群可以促进某些针对肠道的病毒(即脊髓灰质炎病毒、诺沃克病毒、呼肠孤病毒、小鼠乳腺肿瘤病毒)的传播和致病。肠道微生物区系对艾滋病毒感染风险和艾滋病毒感染的其他方面的影响尚不清楚。我们的长期目标是确定肠道微生物区系如何影响艾滋病毒的获取、发病机制、潜伏期、治疗和预防。确定人类肠道微生物区系在HIV-1感染和感染中的作用所需的直接实验是不可能在人类身上进行的。骨髓/肝脏/胸腺(BLT)人源化小鼠与人类免疫细胞系统重组，已被广泛用于研究HIV在体内的传播、发病机制和预防策略。然而，BLT小鼠的肠道微生物群是小鼠的。最近，我们重新衍生和利用了一种无菌免疫缺陷小鼠品系，产生了可与人肠道微生物区系共同定植的无菌BLT小鼠(hum-BLT小鼠)。我们的目标是实现这些新颖和创新的体内模型，我们最近开发的评估肠道微生物区系在直肠HIV-1感染中的作用，作为实现这一目标的第一步。我们的初步数据表明：1)无菌BLT小鼠与人HIV靶细胞进行了强有力的系统重建；2)hum-BLT小鼠的肠道微生物群稳定，并与人类供体接种物保持一致；3)hum-BLT小鼠对直肠感染艾滋病毒很敏感；4)与具有小鼠微生物群的Hum-BLT小鼠(MM-BLT小鼠)相比，人肠道微生物群的存在显著增加了hum-BLT小鼠直肠感染HIV的能力(p=0.01)。根据我们的初步数据，我们假设肠道微生物群的组成影响直肠HIV-1传播风险。我们将建立全面的hum-BLT小鼠，用于研究人类肠道微生物群及其在直肠HIV-1感染中的作用，方法是：1)建立与不同健康人类供体肠道微生物群共同定植的多个hum-BLT小鼠队列，1)评估人类微生物多样性对hum-BLT小鼠肠道微生物区系定植的影响，2)确定人肠道微生物区系对hum-BLT小鼠体内艾滋病毒敏感细胞系统重建、成熟和激活的影响，3)评估肠道微生物区系在直肠HIV-1感染、复制和发病机制中的作用。所获得的信息将填补我们关于人类肠道微生物区系在直肠HIV-1感染中的作用的重要知识空白，这反过来将有助于为未来旨在预防直肠HIV-1传播的临床干预提供信息。这些结果还将验证hum-BLT小鼠作为研究人类肠道微生物组和在人类肠道微生物区系背景下评估艾滋病毒感染的体内平台的有效性。

 DESCRIPTION (provided by applicant): The gut is an important site of HIV acquisition. The majority of new HIV infections in the United States are acquired rectally, and rectal transmission of HIV is a significant mode of HIV acquisition globally. The gut is also a significant site of virs replication, CD4+ T cell depletion, inflammation and microbial translocation. Commensal gut microbiota protect the gut from infection by pathogenic organisms, however, gut microbiota can facilitate the transmission and pathogenesis of certain viruses that target the gut (i.e. polioviru, norovirus, reovirus, mouse mammary tumor virus). The effect of gut microbiota on HIV acquisition risk and other aspects of HIV infection is not known. Our long-term goal is to establish how gut microbiota affect HIV acquisition, pathogenesis, latency, treatment and prevention. The direct experimentation that is needed to establish the role of human gut microbiota in HIV-1 acquisition and infection is not possible to perform in humans. Bone marrow/liver/thymus (BLT) humanized mice are systemically reconstituted with human immune cells and have been extensively utilized to study HIV transmission, pathogenesis and prevention strategies in vivo. However, the gut microbiome of BLT mice is murine. Recently, we rederived and utilized a germ-free immune deficient mouse strain to generate germ-free BLT mice that can be colonized with human gut microbiota (HuM-BLT mice). Our objective here is implement these novel and innovative in vivo models that we recently developed to evaluate the role of gut microbiota in rectal HIV-1 acquisition as the first step towards achieving this goal. Our preliminary data demonstrate: 1) robust systemic reconstitution of germ-free BLT mice with human HIV target cells; 2) the gut microbiome of HuM-BLT mice is stable and recapitulates the human donor inoculum; 3) HuM- BLT mice are susceptible to rectal HIV acquisition; and 4) the presence of human gut microbiota significantly increases rectal HIV acquisition in HuM-BLT mice in comparison to BLT mice with mouse microbiota (MM-BLT mice) (p=0.01). Based on our preliminary data, we hypothesize that the composition of the gut microbiome affects the rectal HIV-1 transmission risk. We will establish the full extent and utility of HuM-BLT mice for the study of the human gut microbiome and its role in rectal HIV-1 acquisition by generating multiple cohorts of HuM-BLT mice colonized with the gut microbiome of different healthy human donors and by 1) assessing the effect of human microbial diversity on gut microbiota colonization in HuM-BLT mice, 2) determining the effect of human gut microbiota on systemic reconstitution, maturation and activation of HIV-susceptible cells in HuM- BLT mice and 3) evaluating the role of gut microbiota in rectal HIV-1 acquisition, replication and pathogenesis. The information obtained will fill an important void in our knowledge regarding the role of human gut microbiota in rectal HIV-1 acquisition that in turn will serve to inform future clinical interventions aimed a preventing rectal HIV-1 transmission. These results will also validate HuM-BLT mice as an in vivo platform for the study of the human gut microbiome and for the evaluation of HIV infection in the context of human gut microbiota.